Autopilot Usage flying IFR
Note: This article reflects ONLY the
opinion of the author and of no other company or individual(s) unless otherwise
indicated
A large number of my IFR students own their own aircraft and
most of these aircraft are relatively new, some in fact are G-1000 equipped.
These advanced technology aircraft are also equipped with some sort of autopilot
device to add even more information being delivered to the IFR student or pilot.
Overview
What's the point here? First of all, IFR
pilots and students are busy enough managing mandatory reporting
points, ATC directions, FAA regulations and approaches without
something else being thrown at them to manage during an IFR flight.
Autopilots themselves both increase this information overload
and help to decrease it at the same time. The
issue is, how does the pilot manage all of this and what should they
expect during an autopilot coupled flight in IMC?
Failures
Technology fails - it's as simple as that.
My limited liability company (Komanetsky Aviation,
LLC) owns two aircraft and one Basic flight simulator. Both
aircraft are Cessna's, circa 2003, a
172SP and a
183T and the
simulator is an Elite Basic ATD
PI-135.
The avionics installed in the aircraft are Bendix King with the KAP
140 autopilot which makes me relatively knowledgeable of this
equipment.
Most G-1000 equipped aircraft today also use the
Bendix King KAP 140 auto pilot which is unfortunately not 100%
integrated with the G-1000 navigation equipment, so, transitioning
into these highly technical aircraft is pretty smooth for Bendix
King experienced pilots.
The KAP 140 WILL fail. Both of my
aircraft have had portions of the KAP 140 replaced at least twice in
their lives which hasn't been that long to date (12/2006). In
three years, I have had to replace devices that are critical to the
operation of the autopilots and one of my aircraft has an autopilot
failure occurring that no one can diagnose.
The currently failing autopilot is behaving like
this:
-
After takeoff, everything is fine. The
autopilot is flying on HDG mode as well as on NAV mode. It
turns when required by the coupled GPS and holds altitude very
well.
-
Within an hour, the autopilot begins to turn the
aircraft when it isn't being asked to. The only way to fix
this is to disengage the autopilot and start flying by hand.
Fortunately, this failure is rather dramatic, so the pilot does
feel it as the plane begins to turn (this is important if flying
in IMC since a gradual slow turn may make the pilot completely
unaware that the plane is turning).
-
If the autopilot is left off for a while, it
will be able to be used again, but it never flies for more than
10 minutes after the initial failure
No avionics shop I have taken this plane to for
repairs has been able to diagnose the problem and many other KAP 140
owners have had failures like this as well. As a safety
precaution, I let
my customers know just what is going on before flying
this particular aircraft.
Think about this type of failure during an approach
while in IMC near minimum altitudes. This is one of the types
of failures I will try and imitate with students that are flying in
a KAP 140 equipped aircraft to assure myself that they can deal with
such a failure. It's not a popular thing to do, but necessary
to assure that the student is managing the flight and not just going
along for the ride.
Autopilot Proficiency
It is extremely important to be proficient in flying
an autopilot equipped aircraft, something that I don't believe needs
to be said. There have been a number of examples of deaths
because of the fact that the pilot was not 100% proficient in the
use of the equipment
During an IMC flight, a pilot was coming into
a northern California airport and was passed off to the tower by
ATC. The pilot hadn't gotten the correct tower frequency,
turned on the autopilot so they could free up their hands to
look up the tower frequency, and the autopilot flew them into a
power tower. The pilot hadn't been trained in the use of
the autopilot and turned on the HDG mode with the heading bug
far to the right of course causing the plane to make a standard
rate turn to the right - something they didn't really want to do
The morale of this and other stories is - train with
the autopilot, make it second nature to you, and practice using it
quite often. Don't become over confident of the technology and assume
it will fail. With an autopilot installed, you are still the
pilot and still must verify that the autopilot is doing what you are
intending for it to do.
Flying proficiency
Once you have become proficient at using your
autopilot you will probably want to use it as much as possible in
all flight conditions. You probably already know where I'm
going with this....
During a recent IFR student flight, I pulled
the AP (auto pilot) circuit breaker to see how the student would
respond. Unfortunately (for the lesson), the system let
out a scream that made us both jump out of our seats and the
student was able to diagnose the problem very quickly.
However, they were very concerned as to why I would have done
such a thing. The result of flying without the autopilot
was a good one - the student was just not ready for their check
ride. Headings were held well, but altitudes were all over
the altimeter and focus on a single instrument instead of a good
scan was observed - not a good prospect for IFR flight.
It is important to understand and use the autopilot
installed in any aircraft you plan on flying, but it is even more
important to keep your flight proficiency skills to their maximum.
The autopilot WILL stop working at some time and you need to make
sure you can effectively pilot the aircraft without the help of this
device.
Your flight instructor (as I do) should have taught
you to expect an engine out condition at any time. They should
have taught you to scan your current location for landing places all
through any flight, just in case an engine out condition
occurs. You need to be prepared! There is absolutely no
difference between an engine out condition and an autopilot out
condition - you need to be able to pilot the plane and conclude the
flight without incident.
The Moral: Prepare for an
autopilot-out condition. Practice flying the aircraft in IMC
(or simulated IMC) without the autopilot, Finding out your
flying skills have diminished because of a lack of practice flying
without an autopilot in NOT a good idea while in IMC.
This page was last modified on
01/05/2007
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